The objective of this research is to systematically characterize the key microsomal cytochrome, P450, and conjugation components in an established, hydrocarbon-transformable cell line, C3H/10T1/2 fibroblasts, and compare them to clones of human embryo fibroblasts. More specifically, we will characterize and purify the benz(a)anthracene inducible cyt. P450 species in the 10T1/2 fibroblasts and examine the site-specific oxidation of benzo(a)pyrene in these mouse and human cells. Factors effecting the subsequent oxidation of BP 7,8 diol to diastereoisomeric diol-oxides and interaction of these diol-oxides with nuclear DNA will also be investigated. The effect of both inhibition and allosteric stimulation of UDP-glucuronyl transferase will be examined in microsomal incubations and whole cells, in particular examining the potential role of this enzyme in controlling the modification of DNA by reactive benzo(a)pyrene derivatives. In order to monitor the effects of altering the cyt. P450 or conjugation enzyme status in these cells, formation of specific BP-DNA base conjugates will be routinely examined. We hope to apply this fundamental information to future studies of chemical-induced mutation and transformation in both mouse and human cell lines.